def setup
  colorMode(RGB)
  stroke(255)
  background(51)
  from = color(218, 165, 32)
  to   = color(72, 61, 139)

  colorMode(RGB) # Try changing to HSB.
  interA = lerpColor(from, to, 0.33)
  interB = lerpColor(from, to, 0.66)

  fill(from)
  rect(10, 20, 20, 60)

  fill(interA)
  rect(30, 20, 20, 60)

  fill(interB)
  rect(50, 20, 20, 60)

  fill(to)
  rect(70, 20, 20, 60)
end